Method of making a cutting foil or plate for shavers

ABSTRACT

A process for producing a cutting foil for dry shavers in which a bearing metal is provided on the underside thereof to minimize wear and friction between the foil and a cutter blade.

United States Patent Futterer [451 Apr. 11, 1972 [54] METHOD OF MAKING A'CUTTING [56] References Cited FOIL 0R PLATE FOR SHAVERS UNITED STATES PATENTS 1 Invenwfl Fulterer, Schonbuhlring 37, switler- 3,498,891 3/1970 Futtetel' ..2o4/11 land [ 22] Filed: May 18, 1970 FOREIGN PATENTS OR APPLICATIONS ,l ,2 l 1 pp Noi: 48,742 1 60 58 12/ 963 Germany 204/11 Primary Examiner-John H. Mack Related Application Data Assistant Examiner-T. Tufariello [62] Division of Ser. NO. 760,01 1, Sept. 16, I968. Attorney-Arthur Schwartz 52 us. (:1 ..204/11, 204/24 [571 ABSTRACT [51] ...C23b 7/00, C23b 5/48 A process for producing a cutting foil for dry shavers in which [58] Field of Search ..204/l l, 24 a bearing metal is provided on the underside thereof to minimize wear and friction between the foil and a cutter blade.

2 Claims, 2 Drawing Figures PATENTEDAPR n ma 3, 655.528

ID\ I\ 4 l W/// M m 1 A b \Q INVENTOR. BODO FUTTERER BY M4 02W;

ATTORNEY.

BACKGROUND AND OBJECTS The present invention concerns a perforated cutting foil or plate for shavers, more particularly for dry shavers having elevated perforation edges, and a method of producing the foil.

Electric shavers generally consist of a fixed cutting plate or cutting foil and a rotating or reciprocating movable cutter head, cutter or cutter foil. These parts are made as hard and smooth as possible to minimize wear and tear and to obtain a long life of the cutting edges.

It has been found, however, that after a short operating time, adhesive forces arise between the cutting elements in contact with one another, especially when the film of grease between the cutting elements has been destroyed by external influences, e.g. skin perspiration. As a result the cutting elements slidingly engaging with one another develop considerable heat owing to the increased friction, the cutting speed is reduced and the output requirement increases and wear and tear increases. Also the cutting action of the shaver also deteriorates as a consequence.

The object of the invention is to provide a perforated cutting foil for shavers which even over long operating periods operates with a low, unvariable friction and which is usable more particularly for dry shavers.

SUMMARY OF THE INVENTION In accordance with the invention the problem is solved by the fact that the underside of the cutting foil which is in contact with a cutter is providing with a coat of a bearing metal which, in the region of the perforation edges, is flush with the plane of the perforation edge elevation. As a result the moving cutter engages particles of the bearing metal spread over the surface of the perforation edge elevations in contact with the cutter. This surface is thereby coated with a thin layer of the bearing metal, thereby stabilizing the frictional properties of the surface.

Preferably tin is used as the bearing metal.

In addition, the surface of the cutter foil may be provided with a hard layer forming the cutting edge. This minimizes the premature wearing of the cutting edges.

The method of producing perforated cutting foils in accordance with the invention is carried out in such a manner that a metal base plate at the perforation regions is covered with an insulating material in order here to prevent the galvanoplastic deposit of metal, whilst the part of the metal base plate remaining free from the insulating material on which the deposit is to be effected, is provided galvanoplastically with a metal coat, the thickness of which is such that the insulating material regions are framed at the edges whereupon the metal coat is passivated, and that a coat of a bearing metal is applied galvanoplastically on the passivated metal coating and subsequently a layer of a solid metal forming the supporting layer of the cutting foil is deposited on the unpassivated surface of the bearing metal.

In accordance with a further development, a still harder metal can be galvanoplastically applied to the surface of the metal carrying the layer to obtain cutting edges having a longer life.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described further, below by way of example, with reference to the accompanying drawings, in

2 which:

FIG. 1 is a sectional view of a foil in the region of a perforation;

FIG. 2 shows a region corresponding to FIG. 1 of a cutting foil on the matrix used for roducin it.

DETAILED DESC ION (g1 THE INVENTION A preferred perforated cutting foil for dry shavers as shown in FIG. 1 in which the cutting foil consists of a carrier layer 1 of, for example, nickel which, in the region of the perforations 2 has an elevated edge 3, the surface of which extends parallel to the plane of the'cutting foil. On the underside of the supporting layer 1, a layer of tin 4 is applied which is also elevated in the region of the perforations and which is flush with the plane of the surface 3. The cutting foil, moreover, has on the surface a layer 5 made of a hard metal which also terminates in the plane of the surface 3 and forms the cutting edge 6. All three layers 1, 4 and 5 in the elevated region of a perforation 2 end of the same level. A cutter 7 is shown which with its cutting edge is supported against the elevated region of the perforation edges.

During its stroke, the cutter 7 moves over the perforation edge surface 8 of the tin layer and forcibly engages tiny tin particles and distributes these over the adjacent perforation edge of the supporting layer 1 and the hard layer 5. This action stabilizes the frictional properties of this surface so that the cutting properties of such a cutting foil are also improved.

A perforated cutting foil is shown in FIG. 2 consisting of the supporting layer 1 and the bearing metal layer 4 on the matrix used for producing it. The matrix includes a metal base plate 9 on which, at the points where the foil is to be perforated, islands 10 of insulating material are provided. An intermediate metal layer 11 is so applied to the metal base plate as to encircle the edges of the islands 10 of insulating material. After the surface of the intermediate metal layer 11 has been passivated, the bearing metal layer 4, such as a layer of tin, is galvanoplastically deposited on the intermediate metal layer 11. After this a further metal layer, for example of nickel, is galvanoplastically deposited on the unpassivated surface of the bearing metal layer 4. Since the surface of the intermediate layer 11 is passivated, the cutting foil, made of bearing metal layer 4 and the supporting layer 1, is readily removed from the matrix. The matrix may then be used to produce further cutting foils.

The perforated cutting foil in accordance with the invention may also be made in an alternative manner, such that a bearing metal layer is applied by evaporation to the underside of the supporting layer 1.

Other known methods are also suitable for application of the bearing metal layer.

I claim:

1. A method of producing perforated cutting foils in which a layer of bearing metal is provided on the underside of the foil in contact with a cutting blade and which is flush with the perforation edge elevations in which a metal base plate is coated at the perforated edges with an insulating material, in order there to prevent a galvanoplastic deposit of metal, whilst a portion remaining free of insulating material of the metal base plate on which the deposit is to occur, is provided galvanoplastically with a metal coating, the thickness of which is such that the insulating material regions are encircled at their edges, whereupon the metal coating is passivated, characterized by the feature that a layer of a bearing metal is galvanoplastically applied on the passivated metal coating and subsequently a solid metal forming the supporting layer of the cutting foil is deposited on the surface of the bearing metal.

2. A method as claimed in claim 1, inwhich a still harder metal is galvanoplastically applied on the surface of the metal forming the supporting layer.

part of a perforated cutting UNITEDflSTATES PATENT OFFICE CERTIFICATE OF COREQTEUN Patent No. 3,655,528 Dated April 11, 1972 Invent r(s) BOdO 'Futterer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading, after "Switzerland", insert assignor to The Gillette Company, Boston, Massachusetts.

Signed and sealed this Sthday of August 1972.

(SEAL) Attest:

EDWARD M.FLE TCHER, JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-105O (10-69) USCOMM-DC 60376-P69 w u.s. GOVERNMENT PRINTING OFFICE I969 0-366-334 

2. A method as claimed in claim 1, inwhich a still harder metal is galvanoplastically applied on the surface of the metal forming the supporting layer. 